Diagnostic and prognostic value of positron emission tomography using [18F] fluorodeoxyglucose in brain tumors

The predominance of the nonoxidative over the more efficient oxidative metabolic pathway results in a higher glucose utilization rate in high-grade than in low-grade tumor tissue, and a consequent increased utilization of the glucose-6-phosphate intermediate. Logically, one would also expect an increased trapping of 2-deoxyglucose-6-phosphate to occur at progressively higher tumor grades according to Sokoloff; s kinetic model [Sokoloff et al., 1977]. This was the authors' rationale for the application of the [18F]-2-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) method to the study of primary CNS tumors. The confirmation of the positive correlation between glioma grade and glycolytic activity by the FDG-PET technique represents the first in vivo human study supporting this relationship. The FDG-PET method, which has been used by our group in over 300 cases of CNS tumors, has proven to be extremely useful in patient management. In the following sections the authors describe their methodology and present the results obtained in the first consecutive 100 cases of brain tumors studied by the FDG-PET technique. This is followed by a discussion of the controversies connected with the quantitation of glucose utilization in CNS tumors